ERYTHROMYCIN
(er-ith-roe-mye'sin)
Akne-Mycin Ery-Tab, Apo-Erythro Base , A/T/S, E-Mycin, Eryc, EryDerm, Ery Pads, EryTab, Erythrocin, Erythromid , Erythromycin Base, Ilotycin, Novorythro , PCE, Robimycin, Ro-Mycin 
ERYTHROMYCIN ESTOLATE
Ilosone, Nororythro 
ERYTHROMYCIN STEARATE
Apo-Erythro-S , Eramycin, Erypar, Ethril, Erythrocin Stearate, SK-Erythromycin
Classifications: antiinfective; macrolide antibiotic
Pregnancy Category: B

Availability

Erythromycin 250 mg, 333 mg, 500 mg tablets, capsules; 2% topical solution; 2% gel; 2% ointment; 2% pledgets; 5% ophthalmic ointment;

Erythromycin Estolate 250 mg capsules; 500 mg tablets; 125 mg/mL, 250 mg/mL suspension;

Erythromycin Stearate 250 mg, 500 mg tablets

Actions

Macrolide antibiotic produced by a strain of Streptomyces erythreus. Bacteriostatic or bactericidal, depending on nature of organism and drug concentration used.

Therapeutic Effects

More active against gram-positive than gram-negative bacteria. Effectiveness against Chlamydia trachomatis is basis for its topical use in prophylaxis of neonatal inclusion conjunctivitis.

Uses

Pneumococcal pneumonia, Mycoplasma pneumoniae (primary atypical pneumonia), acute pelvic inflammatory disease caused by Neisseria gonorrhoeae in females sensitive to penicillin, infections caused by susceptible strains of staphylococci, streptococci, and certain strains of Haemophilus influenzae. Also used in intestinal amebiasis, Legionnaires' disease, uncomplicated urethral, endocervical, and rectal infections caused by Chlamydia trachomatis, for prophylaxis of ophthalmia neonatorum caused by N. gonorrhoeae, C. trachomatis, and for chlamydial conjunctivitis in neonates. Considered an acceptable alternative to penicillin for treatment of streptococcal pharyngitis, for prophylaxis of rheumatic fever and bacterial endocarditis, for treatment of diphtheria as adjunct to antitoxin and for carrier state, and as alternate choice in treatment of primary syphilis in patients allergic to penicillins. Topical applications: Pyodermas, acne vulgaris, and external ocular infections, including neonatal chlamydial conjunctivitis and gonococcal ophthalmia.

Contraindications

Hypersensitivity to erythromycins. Estolate: History of erythromycin-associated hepatitis; liver dysfunction; treatment of skin disorders such as acne or furunculosis; prophylaxis of rheumatic fever.

Cautious Use

Impaired liver function; pregnancy (category B), lactation.

Route & Dosage

Moderate to Severe Infections
Adult: PO 250–500 mg q6h; 333 mg q8h
Child: PO 30–50 mg/kg/d divided q6h Topical Apply ointment to infected eye 1 or more times/d
Neonate: PO 7 d, 10 mg/kg q12h; >7 d, 10 mg/kg q8–12h Topical 0.5–1 cm in conjunctival sac once

Chlamydia trachomatis Infections
Adult: PO 500 mg q.i.d. or 666 mg q8h
Child: Topical Apply 0.5–1 cm ribbon in lower conjunctival sacs shortly after birth

Administration

Oral
Topical

Adverse Effects (1%)

GI: Nausea, vomiting, abdominal cramping, diarrhea, heartburn, anorexia. Body as a Whole: Fever, eosinophilia, urticaria, skin eruptions, fixed drug eruption, anaphylaxis. Superinfections by nonsusceptible bacteria, yeasts, or fungi. Special Senses: Ototoxicity: reversible bilateral hearing loss, tinnitus, vertigo. Digestive: (Estolate) Cholestatic hepatitis syndrome. Skin: (topical use) Erythema, desquamation, burning, tenderness, dryness or oiliness, pruritus.

Diagnostic Test Interference

False elevations of urinary catecholamines, urinary steroids, and AST, ALT (by colorimetric methods).

Interactions

Drug: Serum levels and toxicities of alfentanil, bexarotene, carbamazepine, cevimeline, cilostazol, clozapine, cyclosporine, disopyramide, estazolam, fentanyl, midazolam, methadone, modafinil, quinidine, sirolimus, digoxin, theophylline, triazolam, warfarin are increased. Ergotamine, dihydroergotamine may increase peripheral vasospasm.

Pharmacokinetics

Absorption: Erythromycin base is acid labile; most erythromycins are absorbed in small intestine. Peak: 1–4 h PO. Distribution: Widely distributed to most body tissues; low concentrations in CSF; concentrates in liver and bile; crosses placenta. Metabolism: Partially metabolized in liver. Elimination: Primarily excreted in bile; excreted in breast milk. Half-Life: 1.5–2 h.

Nursing Implications

Assessment & Drug Effects

Patient & Family Education


Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug